CHAPTER V 

 SALMON I DJE (Continued) 



ALMO, the Trout and Atlantic Salmon. The genus 

 Salmo comprises those forms of salmon which have 

 been longest known. As in related genera, the mouth 

 is large, and the jaws, palatines, and tongue are armed with 

 strong teeth. The vomer is flat, its shaft not depressed below 

 the level of the head or chevron (the anterior end). There are 

 a few teeth on the chevron; and behind it, on the shaft, there 

 is either a double series of teeth or an irregular single series. 

 These teeth in the true salmon disappear with age, but in 

 the others (the black-spotted trout) they are persistent. The 

 scales are silvery and moderate or small in size. There are 9 

 to 1 1 developed rays in the anal fin. The caudal fin is truncate, 

 or variously concave or forked. There are usually 40 to 70 

 pyloric cceca, n or 12 branchiostegals, and about 20 (8 + 12) 

 gill-rakers. The sexual peculiarities are in general less marked 

 than in Oncorhynchus ; they are also greater in the anadromous 

 species than in those which inhabit fresh waters. In general 

 the male in the breeding season is redder, its jaws are prolonged, 

 the front teeth enlarged, the lower jaw turned upwards at the 

 end, and the upper jaw notched, or sometimes even perforated, 

 by the tip of the lower. All the species of Salmo (like those of 

 Oncorhynchus) are more or less spotted with black. Unlike 

 the species of Oncorhynchus, the species of Salmo feed more or less 

 while in fresh water, and the individuals for the most part 

 do not die after spawning, although many old males do thus 

 perish. 



The Atlantic Salmon. The large species of Salmo, called 

 salmon by English-speaking people (Salmo salar, Salmo trutta), 

 are marine and anadromous, taking the place in the North 



Atlantic occupied in the North Pacific by the species of Onco- 



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